There is the need for preventing leakage of information such as by a third party using an output device such as a copying machine or a printer capable of outputting information onto paper media to illegally output confidential information onto paper media and sneaking the paper media out, and also unauthorized use of an output device by an unauthorized third party. For that purpose, the use of output devices is often controlled by performing authentication of personal identification by using information storage media such as control cards held by authorized users before permitting the use of the output devices.
There are known conventional techniques in which storage media such as control cards are used for controlling the use of output devices (for example, see Patent Documents 1 and 2).
These conventional techniques for controlling the use of output devices can prevent the use of an output device by third parties other than authorized users who hold information storage media such as control cards. However, a problem with these conventional techniques is that if an authorized user of the output device attempts to use the output device to illegally output confidential information onto paper media with the intention to steal the information, the illegal act cannot be prevented.
Moreover, in many of such cases, no evidence of illegal activities remains. Accordingly, the conventional techniques have little effect of ensuring security because it is difficult to prevent such illegal activities by insiders.
Therefore, the conventional techniques for preventing unauthorized use have no effect of preventing an unauthorized use by authorized users of output devices and one can only rely on morals of authorized users of the output devices to prevent unauthorized use.    [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-10441    [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-98833